Optimal LiFePO4 ratios and loadings for LFP-type cathodes with Single-Ion Conducting Polymer Electrolyte (SICPE) membranes based on PBDT/LiFSI/MPPIFSI for lithium-ion batteries+

Abstract

LiFePO₄ composite cathodes based on LFP, carbon black, and PVDF were prepared with different mass percentages and loadings of the active material, and integrated in CR2032 cells using a Single-Ion Conducting Polymer Electrolyte (SICPE) membrane, alternatively known as Solid Molecular Ionic Composite Electrolyte (SMICE), based on a PBDT/LiFSI/MPPIFSI Molecular Ionic Composite (MIC). The assembled Li-ion battery cells were subjected to a series of tests to gauge their performance. The LFP|SMICE cathodes with a compositional ratio of 60 % and a loading of 1.1 mg cm^–2 in active material displayed the optimal performance, reaching 126 mAh g^–1 at the C/10 current rate, and 93 mAh g^–1 at the 1C current rate, presenting a capacity retention of 90.77 % by the end of the 555th cycle. Our work highlights the potential of combining LFP-type cathodes with single-ion conducting polymer electrolytes to increase the stability and performance of lithium-ion batteries while mitigating the safety issues associated with non-solid electrolytes, and determines the loadings and compositional ratios of LFP in the composite cathodes that present the optimal results in conjunction with SMICE.